Brake shoe and lining grinder



Oct. 12, 1954 J. Y. BLAZEK 2,691,255

BRAKE SHOE AND LINING GRINDER Filed Jan. 2, 1951 4 Sheets-Sheet 1INVENTOR. Jay/v X 54/125? ATmP/VEK Oct. 12, 1954 J. Y. BLAZEK 2,691, 5

BRAKE SHOE AND LINING GRINDER Filed Jan. 2, 1951 4 Sheets-Sheet 2INVENTOR.

5-? .m/w K 81/1256 Oct. 12, 1954 J. Y. BLAZEK 2,691,255

BRAKE SHOE AND LINING GRINDER Filed Jan. 2, 1951 4 Sheets-Sheet 5 /8 f21 E r' f6 INVENTOR.

1954 J. Y. BLAZEK 2,691,255

BRAKE SHOE AND LINING GRINDER Filed Jan. 2, 1951 4 Sheets-Sheet 4INVENTOR. 7 Jd/l/V 1 4,425?

Patented Oct. 12, 1954 BRAKE SHOE AND LINING GRINDER John Y. Blazek,Maple Heights, Ohio, assignor to Lempco Products, Inc., Bedford, Ohio, acorporation of Ohio Application January 2, 1951, Serial No. 204,003

20 Claims. 1

This invention relates to grinding machines for the brake shoes and thebrake shoe linings of automotive vehicles.

The common form of brake shoe is a circularly arcuate body of T-form incross section.

The T-head or flange is generally cylindrical externally and a lining ofwear resisting material is fastened on it.

It has been common practice to grind the lining, either when the shoe isnew, or when the lining is renewed after wear, to true it up tocylindrical contour so as to flt the cylindrical brake drum with whichit engages.

This operation has been necessary because the shoe flange, particularlywhen fabricated from steel, tends to be warped out of true cylindricalform and the lining, if merely attached thereto, would accordingly havea warped braking surface.

The lining has heretofore been fastened to the shoe flange with rivets.To renew a lining, the rivets are driven out, a new lining is rivetedon, and then maybe ground, as aforesaid, to true it up.

Thus in the case of such riveted linings, a service garage needs only adevice or machine to grind the new lining after it has been riveted onthe shoe.

According to more recent practice, however, linings are secured to thebrake shoe flange, by an adhesive or bonding material. To renew alining, the worn lining and bonding material must first be removed by agrinding or cutting opera-' tion. Then the metal surface of the shoemust be given a clean, bright abraded finish of a quality to which thebonding material will adhere. Then the new lining is bonded to the shoeand ground to true it up to cylindrical form.

It would seem to be obvious that the bonded lining could be ground offand the grinding then continued deep enough to grind the underlyingmetal of the shoe to recondition it, as aforesaid, for bonding a newlining thereon, and that existing grinders as referred to above fortruing up the surface of the renewed lining could do this; and that nofurther apparatus is needed and no problem needs to be solved. But suchis not the case because a problem is raised by the bonded linings.

As aforesaid, the shoes are almost always warped, that is, the T-head orflange of the shoe is not truly cylindrical. The flange is only about3%" thick on the average, and it deviates that much from a truecylindrical form in many cases.

If therefore, a grinding machine that was made to grind a cylindricalsurface on a renewed lining were used to grind off the worn bondedlining; and then the grinding were continued deep enough, to abrasivelyclean up the shoe metal over the whole surface to recondition it forbonding a new lining; such continued, cylindrical grinding would, insome places grind away all of the flange, or leave it so thin that itwould not be serviceable as a shoe.

Underlying the present invention is' the conception of a process bywhich the grinding operation is performed in two steps.

First, the worn lining and residue of bonding material are ground offand the metal surface of the shoe reconditioned for bonding, not bygrinding on a cylindrical contour, but by grinding in conformity withthe warped contour of the shoe, whereby the surface on the flange of theshoe, retains its warped form and full original thickness.

Second, when the new lining has been bonded on, it is ground tocylindrical contour.

The invention comprises a single power operated machine by which both ofthese successive grinding steps can be performed.

It is therefore among the objects of the invention to provide animproved grinding process and the grinding machine for performinggrinding operations involved in initially applying, or in renewing,bonded brake shoe linings.

To provide a machine and process by which a brakeshoe lining that hasbeen mounted on a brake shoe by either rivets or bonding, may be truedup to cylindrical form; and also by which in the case of bonded linings,a worn lining can be removed and the shoe reconditioned for the bond ofa new lining without unduly cutting away material of the shoe flange ifit is one that is warped out of cylindrical form.

Another object is to provide an abrasive grinding machine of the classreferred to comprising an abrasive belt, and a mounting for supporting abrake shoe in grinding pressure with the belt, and means to allow theshoe to shift to maintain grinding pressure contact with a warpedliningsupporting surface of the shoe.

Another obj ect is to provide, in an abrasive-belt type of grindingmachine, an improved yieldable backing structure behind the grindingflight of the belt, to hold it in grinding engagement with the work asthe work is fed into the belt.

Another object is to provide in a grinding machine for grinding brakeshoes and linings thereof, means for mounting an arcuate brake shoe foroscillating movement to engage it with a grinding surface of themachine, and improved means for adapting the machine to shoes ofdifferent arcuate radius.

Another object is to provide an improved mounting for an abrasive beltof a belt type grinding machine.

Other objects will be apparent to those skilled in the art to which theinvention pertains.

The invention comprises a machine by which the aforesaid process may bepracticed and the aforesaid objects attained; the actual invention beingset forth in the appended claims; a preferred embodiment of theinvention being fully disclosed in the following description taken inconnection with the accompanying drawing in which:

Figs. 1 and 2 are perspective views of the said embodiment from oppositesides thereof;

Fig. 3 is a side elevational view corresponding to Fig. 1 but to alarger scale, with parts broken away and parts in section;

Fig. 4 is a view looking at the parts of Fig. 3 from the right sidethereof with parts broken away and parts in section;

Fig. 5 is a view looking at the parts of Fig. 3 from the top thereofwith parts broken away and parts in section;

Fig. 6 is a fragmentary view from the plane 66 of Fig. 3 with partsbehind the section plane omitted;

Fig. '7 is a sectional view from the plane 'l-'l of Fig. 6;

Fig. 8 is a sectional view from the plane 88 of Fig. 5;

Fig. 9 is a fragmentary sectional view from the plane 9 of Fig. 5;

Fig. 10 is a perspective view of a brake shoe and lining of the type towhich the invention is related;

Fig. 11 is a fragmentary sectional view from the plane i l of Fig. 3.

Referring to the drawing, there is shown at l, a base, formed to standstably on a bench 2 or like support, and having bolt holes 3, by whichit may be bolted thereto; preferably near the end or side of the benchso that a dust spout 4 to be referred to, may overhang and extend belowthe bench.

A motor 5, on the base has a lower belt pulley 6, on its shaft.

The base has an upright column 1, of plate form, braced by web likebraces 89, and an upright post I0, is secured in a socket H on thecolumn I. A pulley bracket construction, indicated generally at l2, hasan upper belt pulley l3 mounted thereon, directly above the lower pulley6. An abrasive belt M runs on the pulleys 6 and I3, driven by the lowerpulley B. The belt has a working belt flight [5, the abrasive side beingtoward the said column I.

The said upper pulley bracket 12 is constructed to be adjustable topositionally adjust the pulley E3 to provide suitable tension in theabrasive belt l4, and to keep the upper and lower pulleys in parallelismto counteract any tendency of the belt to run off of the pulleys; asfollows, see Figs. 3, 4, and 5.

A bracket head it is vertically slidable on the upper end portion of thepost It), and is splined thereto as at ll to prevent rotation thereon.

A pulley support it, carries a bearing bolt I9, on which the pulley 13has rotary bearing. The head l5, engages the pulley support l8, onmutually abutting surfaces thereof in a vertical plane at 20, parallelto the axes of the pulleys 5 and 1 3. The lower portions of the head andsupport are in the form of depending flanges 2| and 22, and the head andsupport are clamped together at said plane by a cap screw 23, goingthrough an oversized smooth hole 24 in the flange 2! and threaded intothe flange 22.

The pulley support i3, is pivoted on the head it by a pin 25, threadedinto the support I8, and passing through said plane of engagement 20,and into a bore in the head It, in which it is rotatable; the axis ofthe pin being at right angles to the said plane and above the cap screw23, as shown in Fig. 3.

As shown in Fig. 5, the pulley 13, extends laterally from the pulleysupport is and laterally with respect to the axis of the pin 25.

The pulley support can be adjustably rocked on the pin 25, afterloosening the screw 23, which, as will be apparent, will move the rotaryaxis of the pulley IS, in a Vertical plane, to compensate for any upwardor downward inclination thereof with respect to the axis of the lowerpulley 6, and therefore correct for any tendency of the belt to run 01fof the pulleys; and this adjustment is provided for as follows.

A lug 26, on the head it, has a handle screw 21, threaded therethroughextending toward the flange 22 at a point below the pin 25. Upon turningthe screw 21, by its handle 28, in alternate directions (after the screw23 is loosened), the inner end of the screw will rock the support l8,around the pin 25 in one direction, or allow the tension of the belt torock it in the other direction. This adjustment is then fixed bytightening the screw 23.

Below the head 16, the part I0 is threaded as at 29 and a knurled handnut 30 on the thread engages the under side of the head It and supportsit.

The nut 33 is turned by hand to raise or lower the head [5 and pulleysupport l8 attached to it by the pin 25 and the screw 23, to tighten orloosen the abrasive belt M.

The column '1, Figs. 3, 4, and 5 has formed thereon, at its top, arectangular slideway 3| extending horizontally and approximately atright angles to the belt flight l5; and a slide 32 is reciprocable in oron the slideway. The slideway has a slot 33 therein; and a clamp head 34overlapping the slot has a threaded shank 35, extending through the slot33 and screwed into the slide 32. A handle 36 on the head 34 is providedto turn the threaded shank 35, whereby the head 32 may be freed to bemanually slid in the slide- Way to adjustably position it, and thenclamped against sliding when positioned.

A scale pointer 37 on the slide 32, indicates, on a scale 38, theposition of the slide, the scale being in inches in the range ofcommercial brake shoe diameters.

A chuck support 39 is oscillatably pivoted on the slide 32 on ahorizontal axis approximately parallel to the belt flight H), by thefollowing construction, Figs. 2, 5 and 8. The chuck support comprises aflat arm portion 40. A headed pin 4| goes through the arm portion 40 asa bearing therefor, and into a pedestal 32, in which the pin is securedby a set screw 43, the pedestal i2 being mounted on the slide 32 byscrews 4444 and the head of the pin ill holding the arm portion 4|against the pedestal.

The chuck support 39 has a lateral extension 45, and a handle 46 isadjustably slidable in a bore in the extension at right angles to thebelt flight I5, and may be fixed in any slid adjusted position by a pairof wing screws 41-41.

therebetween, and the chuck jaw 58, is movable toward the chuck jaw 48against the spring tension by turning a hand wheel nut 54 on thethreaded end of a stud 55 projecting from the jaw 48 and through aclearance hole 56 in the jaw 58.

Each of the chuck jaws 48 and 58 has rounded corners 51-51, spaced apartvertically, and spaced from the belt flight l5 in the position of theparts in Fig. 3, and equally distant from the axis of the pivot bolt 4l.

In the operation of the machine as thus far described, the web 58 of theshoe (Figs. 3, l0 and 11) is inserted in the space 52 between the chuckjaws 48 and 58 with the flange 59 of the shoe in firm engagement withthe rounded corners 51-51 of the chuck jaws (Fig. 3)

The web 58 is then tightly clamped between the jaws by turning the handwheel nut 54 as described.

The size of the shoe is known, being designated by its diameter (or thediameter of the brake drum with which it is to be used) The slide 32 isunclamped by turning the handle 36 as described and is then slid alongthe slideway 3| until the scale pointer 31 indicates that size on thescale 38, and is then again clamped to the slideway. This adjustmentpositions the pivot pin 4| so that its pivot axis is distant from thebelt flight |5 by One half of the adjustment diameter, or, the radius ofthe shoe.

The handle 46 is then freed by loosening the thumb screws 41-41 and isslid forwardly until the brake shoe lining 68, (or the brak shoe flange59, as the case may be) contacts the belt flight I5. The handle is thenagain secured by the thumb screws 41-41.

The chuck jaws 48-58 and the handle 46 itself are prevented fromrotating about the axis of the handle, by mutually engaging flatsurfaces on the arm 48 and the chuck jaw 48, as indicated at 6| and 82respectively, Figs. 4, 5 and 2.

If now the handles be oscillated up and down about the pivot pin 4| asdescribed, the belt flight will abrade the lining 68 (or the shoe flange59) on a cylindrical surface whose radius is that for which the scalesetting was made.

The brake shoe can be fed forward from time to time as grindingproceeds, by increments as desired, by manually sliding the handle 46 asaforesaid.

To hold the belt flight |5 against the work thus being pressed againstit, an adjustable idler pulley 63, is provided contacting the back sideof the belt flight 5, at the place opposite to the place where the workcontacts its abrasive front side, the construction being as follows.

A bracket 64 Figs. 3 and 6 extends forwardly from the forward part ofthe slideway 3|, being bolted thereto as shown in Fig. 6 by bolts 65-65and has two spaced rigid posts 66-61 rising therefrom; and has anupstanding arm 68 pivoted thereto, the arm 68 being forked andstraddling the bracket 64 as shown in Fig. 7, and

6 a bearing pin 69 going through the bracket and the fork.

A bearing bolt 18 for the idler pulley 6-3 is mounted on the pivoted arm68. The pulley 63 can be adjustably rocked around the pin 69, toward andfrom the belt flight l5, by rocking the arm 68, and positioning it.

This is done by a screw 1| threaded through the post 6-6 and at itsinner end abutting upon one side of the arm 68, and having a wheelhandle 12 on its other end to turn it, to adjustably rock the arm 68 inone direction; and by a yieldable spring 14 on the opposite side of thearm 68, axially aligned with the screw 1| and abutting at its oppositeends upon the arm 68 and post 61, to retract the arm 68 when the screw1| is turned in the other direction; and a lock nut 13 to fix the screw1| when adjustably turned.

The idler pulley has a layer of thick soft rubber 15 on its rim ofuniform thickness, the outer surface 16 of the layer being cylindrical,and the bearing axis of the pulley 63 is parallel to the back of thebelt flight I5, so that when the pulley 63 is adjusted as aforesaid, therubber layer 15 acts as a cushioned backing for the belt flight l5 onthe full width of the belt.

In operation, when the machine is used to true up the surface of a brakelining, such as indicated at 68, Figs. 10 and 3, to cylindrical contour,the handle 46 and chuck jaws 48-58 ar fed for wardly until the liningcontacts the abrasive belt flight l5; and the handle is then fixedv bythe thumb screws 41-41; and is then oscillated up and down, and fromtime to time fed forwardly another increment, as necessary, until theWhole face of the lining is ground by the belt flight IS. The geometryembodied in the device, as described, makes this ground face a truecylinder to the radius or the diameter for which the scale 31-38 is set;even if the flange 59 of the shoe is warped out of cylindrical form.

The rubber layer 15 on the idler pulley 63 behind the belt maintainsgrinding pressure, but yields enough to prevent excess pressure and gouging or scoring so that the grind surface is left smooth. 1

When the machine is used to remove a worn lining and its bondinmaterial, and to condition the surface of the shoe flange 59 for bondingon a renewal lining, the same operation could be performed by continuingto grind by increment adjustment of the handle 46, until the metalsurface of the flange was exposed and cleaned and abraded; but only ifthe flange 59 were not warped, as has been explained.

For this operation therefore, another impor-. tant feature of theconstruction is put into use as follows.

As shown in Figs. 8 and 4, the bolts 44-44 which mount the pedestal 42on the slide 32, go through oversize holes 11 in the pedestal.

A vertical pivot pin 18 is provided in aligned bores in the pedestal 42and slide 31, on which the pedestal has limited oscillatory movement onthe slide 32 on a vertical axis, due to the oversize holes. 7

A manually removable vertical lock pin 19 is projected through alignedbores 88-8| in the pedestal 42 and slide 32, Figs. 4 and 9, radially Idisplaced from the pivot pin 18, and locks the pedestal againstoscillatory movement; this being the condition of the parts when acylindrical surface is to be grounded, as referred to above.

When, as here being considered, the shoe flange 59 is to be ground, thelock pin 19 is withaccuses 7. drawn manually, and may be provided with ahandle on its upper end for that purpose, and a chain 82 may be attachedto it to keep it from becoming lost, if accidentally dropped.

The operator now, upon oscillating the main handle 46 up and down forgrinding in a circular arc as described, may also concurrently move thehandle and the chuck and shoe from side to side; and by inspecting thework as the grinding goes on, may cause the full width of the flange 58to be presented to the flat grinding surface of the belt flight IS, inspite of warpage in the shoe flange. Thus; the belt grinds in conformityto the Warped surface on the shoe, instead of truing it'up to acylindrical surface with the disadvantages hereinbefore described.

A sheet metal hood 83, best shown in Figs. 1 and 2, is provided coveringthe pulleys I3 and 6 and the belt M, and having an opening 84 to exposethe working part of the belt flight i; and communicates at its lower endwith the aforesaid spout 4 by which dust from the grinding operation maybe confined and discharged from the spout into any suitable dustreceptacle, indicated as a bag in Fig. 3 at 85.

The hood may be supported in any suitable manner by the base i and thepost l0, and may be in sections to facilitate removal.

I claim:

1; A grinding machine comprising a main frame rotatably supporting upperand lower spaced belt pulleys; an externally abrasive belt running onthe pulleys and adapted to be driven by a motor driving one of thepulleys, and having a generally vertical planar abrasive belt flight; anelongated rectilinear guideway on the frame extending toward the planeof the belt flight; a bearing construction adjustably positionable alongthe guideway, and lock means for looking it in adjusted position; thebearing construction having a bearing axis generally horizontal andparallel to the plane of the belt flight; a chuck support mounted tooscillate on the bearing construction; said chuck support being formedwith a bore; a unitary chuck and chuck handle assembly mounted on thechuck support, and oscillatable in unison therewith by the handle, thechuck handle having a shank portion received in the bore of the chucksupport and adjustable longitudinally therein to shift the chuck andchuck handle unit bodily toward and from the belt flight to position thechuck in spaced relation to the belt flight, lock means to lock theshank in adjusted positions, and surfaces on the chuck support and chuckmutually engaged on a vertical plane at right angles to the belt flightin all shank adjusted positions.

2. In a grinding machine of the type comprising an elongated planarabrasive belt flight vertical in a position of use, a chuck confrontingthe belt flight and mounted on a chuck support, the chuck supportmounted on a bearing construction the chuck comprising a round shank ina bore on the chuck support, the shank extending out of one end of thebore to provide a handle for oscillating the support and chuck in unisonon the bearing construction the axis of the bearing construction beingdisposed to maintain oscillatory movement of the chuck in longitudinalplanes of the belt flight at right angles thereto; the chuck beingbetween the belt flight and the'other end of the bore and beingadjustably positionable on the chuck support to feed the chuck towardthe belt flight by adjustably positioning the shank with the bore; andthe bearing construction being movable toward and from the plane of thebelt flight and adapted to be locked in adjusted positions to adjustablyvary the distance of the bearing axis from the belt flight; the chuckhaving jaws to grip the web of a brake shoe and having abutmentsengageable by the flange of the brake shoe when its web is gripped bythe chuck, the abutments being spaced apart and equidistant radiallyfrom the bearing axis in all adjusted positions of the axis and all fedpositions of the chuck; the chuck and chuck support having surfacesmutually engaged in a vertical plane at right angles to the belt flightin all adjusted positions of the shank in the bore.

3. In an abrasive belt grinding machine a main frame; a pair of beltpulleys one substantially vertically above the other in a position ofuse rotatably supported by the frame on spaced bearings, and a tensionedabrasive belt running on the pulleys and adapted to be driven by themotor; adjusting means for one of the pulleys to adjust its position toprevent the belt from running 01f due to pulley misalignment,comprising: a support for said'pulley bearing, pivoted relative to themain frame on a substantially horizontal pivot axis at substantially aright angle to the said pulley bearing axis; the support and a portionof the main frame having surfaces mutually engaged with each other onplane at right angles to the pivot axis; lock means normally clampingthe said surfaces together to rigidly lock the support against pivotalmovement, and operable to unlock it; a screw carried by the main frameat an angle to the pivot axis and spaced radially therefrom and abuttingat its end upon the pulley support to rock it on said plane in onedirection, when unlocked, upon turning the screw in one direction, andpermitting the pulley support to be rocked in the other direction bybelt tension when the screw is turned in the other direction; andadjusting means operable to adjust the distance apart of the pulleybearings to adjust the tension in the belt.

4. In an abrasive belt grinding machine a main frame; a pair of beltpulleys one substantially vertically above the other in a position ofuse rotatably supported by the frame on spaced bearings, and a tensionedabrasive belt running on the pulleys and adapted to be driven by amotor; adjusting means for adjusting the tension of the belt and thealignment of the pulleys to prevent the belt from running oiI of thepulleys, comprising: a post on the main frame, generally parallel to thebelt; a head reciprocable on the post; a bearing bracket on the headsupporting the bearing of one of the pulleys; a nut threaded on the postengaging the head and rotatable to effect movement of the head on thepost and the bearing bracket therewith to adjust the tension in thebelt; the bearing bracket being mounted on the head by a substantiallyhorizontal'pivot bearing having an axis at substantially a right angleto the said pulley bearing axis, and the bearing bracket and head beingrigidly clamped together by releasable clamp means upon mutually engagedsurfaces thereof in a common plane at right angles to the pivot axis; ascrew reacting on the post, and an a portion of the bearing bracketradially spaced from the pivot axis, whereby rotation of the screw willpivotally move the bearing bracket when unlocked.

5. In a grinding machine of the type having an abrasive belt running onspaced pulleys and providing a planar abrasive belt flight, against afront portion of which work to be ground is to be engaged with pressure;an idler pulley behind the belt flight engaging the back of said portionof the belt flight; a bearing for the idler pulley mounted on an armpivoted to a backet extending from the frame along one side of the belt,and the pivot being at a point substantially directly under the idlerpulley bearing axis by which the pulley can pivotally rock substantallyat right angles toward and from the back of the belt flightsubstantially without components of movement longitudinally thereof; aspring reacting on the arm and on a portion of the bracket urging thearm and pulley to pivot in one direction, and a screw reacting on thearm and on another portion of the bracket opposing action of the springand adjustable to stop said spring effected movement of the arm, toadjustably position the pulley.

6. In a grinding machine of the type having an abrasive belt running onspaced pulleys and providing a planar abrasive belt flight, against afront portion of which work to be ground is to be engaged with pressure;an idler pulley engaging the back of said belt flight portion, androtatable on a bearing; a mounting for the idler pulley bearingcomprising a bracket on the frame extending along one side of the beltflight, and an arm pivoted on the bracket on an axis generally parallelto and substantially directly under the idler pulley bearing axis andsupporting the pulley bearing; and operable adjusting means to rock thearm on its pivot to move the pulley adjustably substantially at rightangles toward and from the back of the belt flight portion andsubstantially without components of movement longitudinally thereof.

7. In a grinding machine, a frame, an abrasive belt running on spacedbelt pulleys on the frame, providing a planar abrasive belt flighttherebetween substantially vertical in a position of use; a chuckholder; a work holding chuck provided with a handle, mounted on thechuck holder in front of the belt flight by a shank of the handle in abore of the chuck holder extending toward the belt flight; a bearing, onthe frame for the chuck holder, having a bearing axis on which the chuckholder and chuck may be manually oscillated in unison by the handle, inlongitudinal planes of the belt flight at right angles to the plane ofthe belt flight, whereby a cylindrical surface may 'be ground on a workpiece held by the chuck; the said bearing being adjustably positionableon the frame toward and from the plane of the belt flight to vary theradius of the cylindrical surface to be ground; the chuck being movableon the chuck holder upon longitudinal movement of the shank in the boreby the handie, to feed the work to the belt flight; the chuck holder andchuck having surfaces mutually engaged on a common vertical plane atright angles to the belt flight and preventing rotation of the shank inthe bore.

8. In a grinding machine a frame, an abrasive belt running on spacedbelt pulleys on the frame, providing a planar abrasive belt flighttherebetween; a chuck holder; a work holding chuck provided with ahandle, mounted on the chuck holder in front of the belt flight by ashank of the handle in a bore of the chuck holder extending toward thebelt flight; a bearing on the frame for the chuck holder, having abearing axis on whichthe chuck and chuck holder may be manuallyoscillated in unison by the handle in longitudinal planes-of the beltflight at right angles to the plane of the belt flight, whereby acylindrical surface may be ground on a work piece held by the chuck; thesaid bearing being adjustably positionable on the frame toward and fromthe plane of the belt flight to vary the radius of the cylindricalsurface to be ground; the chuck being movable on the chuck holder by thelongitudinal movement of the shank in the bore by the handle to feed thework to the belt flight; the chuck holder bearing being pivotallymounted on the frame on a pivot axis generally at right angles to thesaid bearing axis, and lock means locking it against pivoting when acylindrical surface is to be ground; and the lock being releasable topermit alternate selected pivoting movements of the chuck holder andchuck by the handle concurrently with said oscillatory move ment wherebya warped circular surface may be ground on the work; the chuck holderand chuck having surfaces mutually engaged on a common vertical plane atright angles to the belt flight ant preventing rotation of the shank inthe bore.

9. A grinding machine for grinding cylindrical surfaces, or, optionally,circular warped surfaces, on a work piece, comprising; a main frame; apower driven element having a planar abrasive grinding surface; a chucksupport oscillatably mounted on a bearing carried by the frame; a workholding chuck confronting the grinding surface and provided with ahandle and mounted on the chuck support, by a handle shank in a bore ofthe chuck support; and oscillatable in unison with the chuck support, bythe handle; the chuck being adjustably positionable on the chuck supportto feed the chuck toward the grinding surface by longitudinal movementof the shank in the bore; the bearing axis of the chuck holder disposedso that oscillations of the chuck holder and chuck will cause acylindrical surface to be ground on a work piece mounted in the chuck;the chuck support bearing being pivoted to the frame on a pivot havingan axis generally at right angles to the axis of the chuck holderbearing; releasable lock means locking the bearing against pivoting whena cylindrical surface is to be ground; the chuck holder and chuck beingoscillatable on the pivot when the lock is released whereby the chuckholder and chuck may be oscillated on the pivot and on the bearingconcurrently with selected movements to grind a circular warped surfaceon a work piece in the chuck; the chuck holder and chuck having surfacesmutually engaged on a common vertical plane at right angles to the beltflight and preventing rotation of the shank in the bore.

10. A grinding machine comprising a main frame rotatably supportingupper and lower spaced belt pulleys; an externally abrasive belt runningon the pulleys and adapted to be driven by a motor driving one of thepulleys, and having a generally vertical planar abrasive belt flight; anelongated rectilinear guideway on the frame extending toward the planeof the belt flight; a bearing support adjustably positionable along theguideway, and lock means for locking it in adjusted position; a bearingconstruction on the bearing support having an axis generally horizontaland parallel to the plane of the belt flight; a chuck support mounted tooscillate on the bearing construction; a unitary chuck and handleassembly mounted on the chuck support by a shank of the handle in a boreof the chuck holder extending toward the belt flight, and oscillatablein unison with the chuck holder by the handle, the chuck and handleassembly being adjustably movable by longitudinal movement of the shankin the bore to position the chuck in spaced relation to the belt flight,and lock means to lock the chuck and handle assembly in adjustedpositions; the bearing construction having a pivot connection with thebearing support on a generally vertical axis, and a releasable locklocking the bearing construction against pivoting; andthe chuck holder,bearing construction, and chuck, being oscillatable by the handle aboutthe pivot axis concurrently with said oscillation on the bearingconstruction, when the lock is released; the chuck holder and chuckhaving surfaces mutually engaged on a common vertical plane at rightangles to the belt flight and preventing rotation of the shank in thebore.

11. The method of reconditioning for use a brake shoe having a wornlining bonded to a brake shoe flange of generally cylindrical form butwhich flange is warped out of true cylindrical form, which includes:feeding the shoe toward a planar grinding surface to grind the liningand oscillating the shoe on a first axis parallel to the abradingsurface while concurrently oscillating the shoe around a second axis atan angle to the first axis, to cause grinding to occur on a warpedcircular contour conforming to the warped contour of the flange;continuing as aforesaid until the worn lining and bonding material areground off and a clean warped metal surface on the warped flange isexposed; then bonding a new lining on the warped flange; then feedingthe shoe toward a planar grinding surface to grind the lining andoscillating the shoe on an axis parallel to the planar grinding surfaceto grind a true cylindrical surface on the lining.

12. A grinding machine for grinding a cylindrical surface on the liningof a brake shoe of the type comprising a generally cylindrical flangeand a web at right angles thereto; the machine comprising a main framerotatably supporting upper and lower belt pulleys; an abrasive beltrunning on the pulleys and adapted to be driven by a motor and having aplanar abrasive belt flight generally vertical in a position of use; afree end bearing pin mounted on a support; the support mounted forpositioning movement on the frame, and guide means constraining it tomove toward and from the belt flight, and maintaining the axis of thebearing pin generally horizontal and parallel to the plane of the beltflight, and clamp means to fix the support and pin in selectedpositions; a chuck support mounted to oscillate on the bearing pin; achuck comprising an elongated round shank in a bore extending toward thebelt flight and provided on the oscillatable chuck support andcomprising chuck jaws connected to the shank and between an end of thebore and the belt flight and operable to grip the shoe web therein; theshank being manually adjustable longitudinally in the bore to move thechuck jaws toward or from-the belt flight; means to lock the shank inadjusted positions; the chuck and the oscillatable support having planarsurfaces in mutual contact on a vertical plane at right angles to thebelt flight, preventing rotation of the shank in the bore, in alladjusted positions thereof and the shank continuing into a handle beyondthe other end of the bore for oscillating the chuck support and chuck onthe bearing pin.

13. A grinding machine comprising a main frame rotatably supportingupper and lower belt pulleys; an externally abrasive belt running on thepulleys and adapted to be driven by a motor and having a generallyplanar abrasive belt flight vertical in a position of use; a bearingconstruction supporting a bearing and mounted for positioning movementon the frame, and guide means constraining it to move toward and fromthe belt flight rectilinearly and at right angles to the plane of thebelt flight, and in all moved positions maintaining the bearing axisgenerally horizontal and parallel to the plane of the belt flight, andclamp means to fix it in moved positions; a chuck support mounted tooscillate on the bearing; a chuck comprising an elongated round shank ina bore extending toward the belt flight and provided on the oscillatablechuck support and comprising chuck jaws connected to the shank andbetween an end of the bore and the belt flight; the shank being manuallyadjustable longitudinally in the bore to move the chuck jaws toward orfrom the belt flight; means to lock the shank in adjusted positions; thechuck and the oscillatable support having planar surface in mutualcontact on a vertical plane at right angles to the belt flight;preventing rotation of the shank in the bore, in all adjusted positionsthereof and the shank continuing into a handle beyond the other end ofthe bore for oscillating the chuck support and chuck on the bearing.

14. An abrading machine comprising a base having a generally horizontalplatform portion, an upright column extending upwardly from one end ofthe platform portion, a motor on the other end of the platform portionof the base, said motor having a shaft rotatable about a horizontalaxis, a pulley on the motor shaft, an upright post on the column, apulley mounted on the post for rotation about a horizontal axis spacedvertically above the motor shaft axis, an annular belt trained about thepulleys, said belt having spaced flights and an outwardly directedabrasive surface, bracket means supported by the column and extendingfrom the latter over the top of the motor, an idler pulley disposedbetween the flights of the belt, means mounting the idler pulley on thebracket in substantially line contact supporting relation to one of thebelt flights, a member mounted on the column for relativeslidingmovement toward and away from said one belt flight, a work supportmounted on the slidable member for turning movement about a horizontalaxis, the work support turning axis being carried laterally to and fromthe belt during said sliding movement, and work clamping means mountedon the work support to turn with the latter, the rotational axis of theidler pulley and the turning axis of the work support defining a planewhich intersects the said one flight of the belt substantially alongsaid line of supporting contact.

15. An abrading machine comprising a base having a generally horizontalplatform portion, an upright column extending upwardly from one end ofthe platform portion, a motor on the other end of the platform portionof the base, said motor having a shaft rotatable about a horizontalaxis, a pulley on the motor shaft, an upright post on the column, apulley mounted on the post for rotation about a horizontal axis spacedvertically above the motor shaft axis, an annular belt trained about thepulleys, said belt having spaced flights and an outwardly directedabrasive surface, bracket means supported by the column and extendingfrom the latter over the top of the motor, an idler pulley disposedbetween the flights of the belt, means mounting the idler pulley on thebracket in substantially line contact supporting relation to one of thebelt flights, a member mounted on the column for relative slidingmovement toward and away from said one belt flight, a work supportmounted on the slidable member for turning movement about a horizontalaxis, the work support turning axis being carried laterally to and fromthe belt during said sliding movement, and work clamping means mountedon the work support to turn with the latter and for sliding movementrelative to the slidable member along an axis substantially normal tothe belt and intersecting said horizontal turning axis of the worksupport, the rotational axis of the idler pulley and the turning axis ofthe work support defining a plane which intersects the said one flightof the belt substantially along said line of supporting contact.

16. An abrading machine comprising a base having a generally horizontalplatform portion, an upright column extending upwardly from one end ofthe platform portion, a motor on the other end of the platform portionof the base, said m0- tor having a shaft rotatable about a horizontalaxis, a pulley on the motor shaft, an upright post on the column, apulley mounted on the post for rotation about a horizontal axis spacedvertically above the motor shaft axis, an annular belt trained about thepulley, said belt having spaced flights and an outwardly directedabrasive surface, bracket means supported by the column and extendingfrom the latter over the top of the motor, an idler pulley disposedbetween the flights of the belt, means mounting the idler pulley on thebracket in substantially line contact supporting relation to one of thebelt flights, a member mounted on the column for relative slidingmovement toward and away from said one belt flight, a work support, andmeans mounting the work support on the slidable member for turningmovement about a horizontal axis and swinging movement about a verticalaxis, the rotational axis of the idler pulley and the turning axis ofthe work support defining a plane which intersects the said one flightof the belt substantially along said line of supporting contact.

1'7. An abrading machine comprising a base having a generally horizontalplatform portion, an upright column extending upwardly from one end ofthe platform portion, a motor on the other end of the platform portionof the base, said motor having a shaft rotatable about a horizontalaxis, a pulley on the motor shaft, an upright post on the column, apulley mounted on the post for rotation about a horizontal axis spacedvertically above the motor shaft axis, an annular belt trained about thepulleys, said belt having spaced flights and an outwardly directedabrasive surface, backing means mounted on the column and extendinglaterally therefrom in cantilever fashion between the flights of thebelt and in supporting relation to one such flight, a member mounted onone side of the column and projecting laterally from the column in thesame direction as the belt backing means, said member being slidable onthe column and guided thereby for rectilinear movement along a linesubstantially normal to the plane of said one flight of the abrasivebelt, a work support, and means mounting the work support on theslidable member for turning movement about a substan tially horizontalaxis.- 1 18. An abrading machine comprising a base having a generallyhorizontal platform portion, an upright column extending upwardly fromone endof the platform portion, a motor on the other end of the platformportion of the base, said motor having, a shaft rotatable about ahorizontal axis, a pulley ,on the motor shaft, a pulley mounted on thepost for rotation, about a horizontal axis spaced vertically above themotor shaft axis, the vertical projections of said pulleys both beingwholly 'outside the platform portion of the base, an annular belttrained about the pulleys, said belt having spaced flights and anoutwardly directed abrasive surface, backing means mounted on the columnand extending laterally therefrom in cantilever fashion between theflights of the belt and in supporting relation to one such flight, amember mounted on one side of the column and projecting laterally fromthe column in the same direction as the belt backing means, said member:being slidable on the column and guided thereby for rectilinearmovement along a line substantially normal to the plane of said oneflight of the abrasive belt, a work support, and means mounting the worksupport on the slidable member for turning movement about asubstantially horizontal axis.

19. A method of reconditioning a brake shoe of the type comprising ametal member having a surface that is substantially a segment of acylinder and a composition lining bonded to such surface, which methodcomprises feeding the shoe and a substantially flat moving abradingsurface relatively together to abrade the lining while concurrentlyoscillating the shoe about angularly disposed axes one of which isparallel to the abrading surface to provide a clean metal surface on themetal member, bonding a new lining of wear resistant compositionmaterial to the clean metal surface so provided, and feeding the shoetoward a substantially planar grinding surface to grind the new liningwhile oscillating the shoe about an axis parallel to said planargrinding surface to grind a true cylindrical surface on the new lining.

20. In the method of finishing a brake shoe of the type comprising asegmental metal member having a substantially cylindrical surface and acylindrically surfaced composition lining secured against such metalmember surface and conformed thereto, which method comprises drawing aflexible abrasive sheet element relatively across the lining, theimprovement which comprises in combination tensioning the sheet abrasiveelement to provide on one side a substantially planar abrasive surface,moving the shoe relatively toward and against said one side of thetensioned sheet abrasive element to establish substantially line contactbetween the substantially cylindrical surface of the lining and theplanar abrasive surface of the tensioned abrasive element, supportingthe tensioned abrasive element by pressure applied yieldingly to theother side thereof substantially along a line paralleling the contactline and spaced from the latter by the thickness of the abrasiveelement, and continuously drawing the abrasive element across thecylindrical surface of the lining of the shoe in a movement whichadvances all portions of the abrasive surface along said line contact atsubstantially the same linear rate of speed while turning the brake shoeabout an axis paralleling both the support and contact lines Number NameDate whereby the cylindrical surface of the lining is 2,102,915 RishelDec. 21, 1937 drawn progressively across the planar surface of 2,212,179Martin Aug. 20, 1940 the abrasive element at said line of contact and2,309,620 Blazek et a1 Feb. 2, 1943 at such contact line the saidabrasive surface is 5 2,367,107 Emmons Jan. 9, 1945 maintainedsubstantially tangent to the cylin- 2,408,491 Strickland Oct. 1, 1946drical liner surface with all portions of the 2,431,795 Elmes Dec. 2,1947 abrasive element moving relatively circumfer- 2,463,287 KruegerMar. 1, 1949 entially of the liner in all turned positions of 2,469,735Lindsay et al May 10, 1949 th b k h 10 2,480,618 Tresidder Aug. 30, 1949References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,906,201 Simpson Apr. 25, 1933 15

